Files
futur4j/futur-api/src/main/java/dev/tommyjs/futur/promise/AbstractPromise.java
2025-01-07 14:51:37 +00:00

592 lines
20 KiB
Java

package dev.tommyjs.futur.promise;
import dev.tommyjs.futur.function.ExceptionalConsumer;
import dev.tommyjs.futur.function.ExceptionalFunction;
import dev.tommyjs.futur.function.ExceptionalRunnable;
import dev.tommyjs.futur.function.ExceptionalSupplier;
import dev.tommyjs.futur.util.PromiseUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.slf4j.Logger;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.VarHandle;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.function.Consumer;
@SuppressWarnings({"FieldMayBeFinal", "unchecked"})
public abstract class AbstractPromise<T, FS, FA> implements CompletablePromise<T> {
private static final VarHandle COMPLETION_HANDLE;
private static final VarHandle LISTENERS_HANDLE;
static {
try {
MethodHandles.Lookup lookup = MethodHandles.lookup();
COMPLETION_HANDLE = lookup.findVarHandle(AbstractPromise.class, "completion", PromiseCompletion.class);
LISTENERS_HANDLE = lookup.findVarHandle(AbstractPromise.class, "listeners", Collection.class);
} catch (ReflectiveOperationException e) {
throw new ExceptionInInitializerError(e);
}
}
private final Sync sync;
private volatile Collection<PromiseListener<T>> listeners;
private volatile PromiseCompletion<T> completion;
public AbstractPromise() {
this.sync = new Sync();
this.listeners = Collections.EMPTY_LIST;
this.completion = null;
}
public abstract @NotNull AbstractPromiseFactory<FS, FA> getFactory();
private void runCompleter(@NotNull CompletablePromise<?> promise, @NotNull ExceptionalRunnable completer) {
try {
completer.run();
} catch (Error e) {
promise.completeExceptionally(e);
throw e;
} catch (Throwable e) {
promise.completeExceptionally(e);
}
}
private <V> @NotNull Runnable createCompleter(
T result,
@NotNull CompletablePromise<V> promise,
@NotNull ExceptionalFunction<T, V> completer
) {
return () -> {
if (!promise.isCompleted()) {
runCompleter(promise, () -> promise.complete(completer.apply(result)));
}
};
}
protected @NotNull Logger getLogger() {
return getFactory().getLogger();
}
@Override
public T get() throws InterruptedException, ExecutionException {
sync.acquireSharedInterruptibly(1);
return joinCompletion();
}
@Override
public T get(long time, @NotNull TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
boolean success = sync.tryAcquireSharedNanos(1, unit.toNanos(time));
if (!success) {
throw new TimeoutException("Promise stopped waiting after " + time + " " + unit);
}
return joinCompletion();
}
@Override
public T await() {
try {
sync.acquireSharedInterruptibly(1);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
PromiseCompletion<T> completion = Objects.requireNonNull(getCompletion());
if (completion.isSuccess()) return completion.getResult();
throw new CompletionException(completion.getException());
}
private T joinCompletion() throws ExecutionException {
PromiseCompletion<T> completion = Objects.requireNonNull(getCompletion());
if (completion.isSuccess()) return completion.getResult();
throw new ExecutionException(completion.getException());
}
@Override
public @NotNull Promise<T> fork() {
CompletablePromise<T> fork = getFactory().unresolved();
PromiseUtil.propagateCompletion(this, fork);
return fork;
}
@Override
public @NotNull Promise<Void> thenRun(@NotNull ExceptionalRunnable task) {
return thenApply(_ -> {
task.run();
return null;
});
}
@Override
public @NotNull Promise<Void> thenConsume(@NotNull ExceptionalConsumer<T> task) {
return thenApply(result -> {
task.accept(result);
return null;
});
}
@Override
public <V> @NotNull Promise<V> thenSupply(@NotNull ExceptionalSupplier<V> task) {
return thenApply(_ -> task.get());
}
@Override
public <V> @NotNull Promise<V> thenApply(@NotNull ExceptionalFunction<T, V> task) {
CompletablePromise<V> promise = getFactory().unresolved();
addDirectListener(
res -> createCompleter(res, promise, task).run(),
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public <V> @NotNull Promise<V> thenCompose(@NotNull ExceptionalFunction<T, Promise<V>> task) {
CompletablePromise<V> promise = getFactory().unresolved();
thenApply(task).addDirectListener(
nestedPromise -> {
if (nestedPromise == null) {
promise.complete(null);
} else {
PromiseUtil.propagateCompletion(nestedPromise, promise);
PromiseUtil.propagateCancel(promise, nestedPromise);
}
},
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public @NotNull Promise<Void> thenRunSync(@NotNull ExceptionalRunnable task) {
return thenApplySync(_ -> {
task.run();
return null;
});
}
@Override
public @NotNull Promise<Void> thenRunDelayedSync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit) {
return thenApplyDelayedSync(_ -> {
task.run();
return null;
}, delay, unit);
}
@Override
public @NotNull Promise<Void> thenConsumeSync(@NotNull ExceptionalConsumer<T> task) {
return thenApplySync(result -> {
task.accept(result);
return null;
});
}
@Override
public @NotNull Promise<Void> thenConsumeDelayedSync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
return thenApplyDelayedSync(result -> {
task.accept(result);
return null;
}, delay, unit);
}
@Override
public <V> @NotNull Promise<V> thenSupplySync(@NotNull ExceptionalSupplier<V> task) {
return thenApplySync(_ -> task.get());
}
@Override
public <V> @NotNull Promise<V> thenSupplyDelayedSync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit) {
return thenApplyDelayedSync(_ -> task.get(), delay, unit);
}
@Override
public <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task) {
CompletablePromise<V> promise = getFactory().unresolved();
addDirectListener(
res -> runCompleter(promise, () -> {
Runnable runnable = createCompleter(res, promise, task);
FS future = getFactory().getSyncExecutor().run(runnable);
promise.addDirectListener(_ -> getFactory().getSyncExecutor().cancel(future));
}),
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
CompletablePromise<V> promise = getFactory().unresolved();
addDirectListener(
res -> runCompleter(promise, () -> {
Runnable runnable = createCompleter(res, promise, task);
FS future = getFactory().getSyncExecutor().run(runnable, delay, unit);
promise.addDirectListener(_ -> getFactory().getSyncExecutor().cancel(future));
}),
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public <V> @NotNull Promise<V> thenComposeSync(@NotNull ExceptionalFunction<T, Promise<V>> task) {
CompletablePromise<V> promise = getFactory().unresolved();
thenApplySync(task).addDirectListener(
nestedPromise -> {
if (nestedPromise == null) {
promise.complete(null);
} else {
PromiseUtil.propagateCompletion(nestedPromise, promise);
PromiseUtil.propagateCancel(promise, nestedPromise);
}
},
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public @NotNull Promise<Void> thenRunAsync(@NotNull ExceptionalRunnable task) {
return thenApplyAsync(_ -> {
task.run();
return null;
});
}
@Override
public @NotNull Promise<Void> thenRunDelayedAsync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit) {
return thenApplyDelayedAsync(_ -> {
task.run();
return null;
}, delay, unit);
}
@Override
public @NotNull Promise<Void> thenConsumeAsync(@NotNull ExceptionalConsumer<T> task) {
return thenApplyAsync(result -> {
task.accept(result);
return null;
});
}
@Override
public @NotNull Promise<Void> thenConsumeDelayedAsync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
return thenApplyDelayedAsync(result -> {
task.accept(result);
return null;
}, delay, unit);
}
@Override
public <V> @NotNull Promise<V> thenSupplyAsync(@NotNull ExceptionalSupplier<V> task) {
return thenApplyAsync(_ -> task.get());
}
@Override
public <V> @NotNull Promise<V> thenSupplyDelayedAsync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit) {
return thenApplyDelayedAsync(_ -> task.get(), delay, unit);
}
@Override
public <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task) {
CompletablePromise<V> promise = getFactory().unresolved();
addDirectListener(
(res) -> runCompleter(promise, () -> {
Runnable runnable = createCompleter(res, promise, task);
FA future = getFactory().getAsyncExecutor().run(runnable);
promise.addDirectListener(_ -> getFactory().getAsyncExecutor().cancel(future));
}),
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
CompletablePromise<V> promise = getFactory().unresolved();
addDirectListener(
res -> runCompleter(promise, () -> {
Runnable runnable = createCompleter(res, promise, task);
FA future = getFactory().getAsyncExecutor().run(runnable, delay, unit);
promise.addDirectListener(_ -> getFactory().getAsyncExecutor().cancel(future));
}),
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public <V> @NotNull Promise<V> thenComposeAsync(@NotNull ExceptionalFunction<T, Promise<V>> task) {
CompletablePromise<V> promise = getFactory().unresolved();
thenApplyAsync(task).addDirectListener(
nestedPromise -> {
if (nestedPromise == null) {
promise.complete(null);
} else {
PromiseUtil.propagateCompletion(nestedPromise, promise);
PromiseUtil.propagateCancel(promise, nestedPromise);
}
},
promise::completeExceptionally
);
PromiseUtil.propagateCancel(promise, this);
return promise;
}
@Override
public @NotNull Promise<T> thenPopulateReference(@NotNull AtomicReference<T> reference) {
return thenApplyAsync(result -> {
reference.set(result);
return result;
});
}
@Override
public @NotNull Promise<Void> erase() {
return thenSupply(() -> null);
}
@Override
public @NotNull Promise<T> addAsyncListener(@NotNull AsyncPromiseListener<T> listener) {
return addAnyListener(listener);
}
@Override
public @NotNull Promise<T> addAsyncListener(@Nullable Consumer<T> successListener, @Nullable Consumer<Throwable> errorListener) {
return addAsyncListener(res -> {
if (res.isSuccess()) {
if (successListener != null) successListener.accept(res.getResult());
} else {
if (errorListener != null) errorListener.accept(res.getException());
}
});
}
@Override
public @NotNull Promise<T> addDirectListener(@NotNull PromiseListener<T> listener) {
return addAnyListener(listener);
}
@Override
public @NotNull Promise<T> addDirectListener(@Nullable Consumer<T> successListener, @Nullable Consumer<Throwable> errorListener) {
return addDirectListener(res -> {
if (res.isSuccess()) {
if (successListener != null) successListener.accept(res.getResult());
} else {
if (errorListener != null) errorListener.accept(res.getException());
}
});
}
private @NotNull Promise<T> addAnyListener(PromiseListener<T> listener) {
Collection<PromiseListener<T>> prev = listeners, next = null;
for (boolean haveNext = false;;) {
if (!haveNext) {
next = prev == Collections.EMPTY_LIST ? new ConcurrentLinkedQueue<>() : prev;
if (next != null) next.add(listener);
}
if (LISTENERS_HANDLE.weakCompareAndSet(this, prev, next))
break;
haveNext = (prev == (prev = listeners));
}
if (next == null) {
if (listener instanceof AsyncPromiseListener) {
callListenerAsync(listener, Objects.requireNonNull(getCompletion()));
} else {
callListenerNow(listener, Objects.requireNonNull(getCompletion()));
}
}
return this;
}
private void callListenerAsync(PromiseListener<T> listener, PromiseCompletion<T> res) {
try {
getFactory().getAsyncExecutor().run(() -> callListenerNow(listener, res));
} catch (RejectedExecutionException ignored) {
} catch (Exception e) {
getLogger().warn("Exception caught while running promise listener", e);
}
}
private void callListenerNow(PromiseListener<T> listener, PromiseCompletion<T> res) {
try {
listener.handle(res);
} catch (Error e) {
getLogger().error("Error caught in promise listener", e);
throw e;
} catch (Throwable e) {
getLogger().error("Exception caught in promise listener", e);
}
}
@Override
public @NotNull Promise<T> onSuccess(@NotNull Consumer<T> listener) {
return addAsyncListener(listener, null);
}
@Override
public @NotNull Promise<T> onError(@NotNull Consumer<Throwable> listener) {
return addAsyncListener(null, listener);
}
@Override
public @NotNull Promise<T> logExceptions(@NotNull String message) {
Exception wrapper = new DeferredExecutionException();
return onError(e -> getLogger().error(message, wrapper.initCause(e)));
}
@Override
public <E extends Throwable> @NotNull Promise<T> onError(@NotNull Class<E> type, @NotNull Consumer<E> listener) {
return onError(e -> {
if (type.isAssignableFrom(e.getClass())) {
//noinspection unchecked
listener.accept((E) e);
}
});
}
@Override
public @NotNull Promise<T> onCancel(@NotNull Consumer<CancellationException> listener) {
return onError(CancellationException.class, listener);
}
@Override
public @NotNull Promise<T> timeout(long time, @NotNull TimeUnit unit) {
Exception e = new CancellationException("Promise timed out after " + time + " " + unit.toString().toLowerCase());
return completeExceptionallyDelayed(e, time, unit);
}
@Override
public @NotNull Promise<T> maxWaitTime(long time, @NotNull TimeUnit unit) {
Exception e = new TimeoutException("Promise stopped waiting after " + time + " " + unit.toString().toLowerCase());
return completeExceptionallyDelayed(e, time, unit);
}
private Promise<T> completeExceptionallyDelayed(Throwable e, long delay, TimeUnit unit) {
runCompleter(this, () -> {
FA future = getFactory().getAsyncExecutor().run(() -> completeExceptionally(e), delay, unit);
addDirectListener(_ -> getFactory().getAsyncExecutor().cancel(future));
});
return this;
}
private void handleCompletion(@NotNull PromiseCompletion<T> cmp) {
if (!COMPLETION_HANDLE.compareAndSet(this, null, cmp)) return;
sync.releaseShared(1);
Iterator<PromiseListener<T>> iter = ((Iterable<PromiseListener<T>>) LISTENERS_HANDLE.getAndSet(this, null)).iterator();
try {
while (iter.hasNext()) {
PromiseListener<T> listener = iter.next();
if (listener instanceof AsyncPromiseListener) {
callListenerAsync(listener, cmp);
} else {
callListenerNow(listener, cmp);
}
}
} finally {
iter.forEachRemaining(v -> callListenerAsyncLastResort(v, cmp));
}
}
private void callListenerAsyncLastResort(PromiseListener<T> listener, PromiseCompletion<T> completion) {
try {
getFactory().getAsyncExecutor().run(() -> callListenerNow(listener, completion));
} catch (Throwable ignored) {}
}
@Override
public void cancel(@NotNull CancellationException e) {
completeExceptionally(e);
}
@Override
public void complete(@Nullable T result) {
handleCompletion(new PromiseCompletion<>(result));
}
@Override
public void completeExceptionally(@NotNull Throwable result) {
handleCompletion(new PromiseCompletion<>(result));
}
@Override
public boolean isCompleted() {
return completion != null;
}
@Override
public @Nullable PromiseCompletion<T> getCompletion() {
return completion;
}
@Override
public @NotNull CompletableFuture<T> toFuture() {
CompletableFuture<T> future = new CompletableFuture<>();
addDirectListener(future::complete, future::completeExceptionally);
future.whenComplete((_, e) -> {
if (e instanceof CancellationException) {
this.cancel();
}
});
return future;
}
private static class DeferredExecutionException extends ExecutionException {
}
private static final class Sync extends AbstractQueuedSynchronizer {
private Sync() {
setState(1);
}
@Override
protected int tryAcquireShared(int acquires) {
return getState() == 0 ? 1 : -1;
}
@Override
protected boolean tryReleaseShared(int releases) {
int c1, c2;
do {
c1 = getState();
if (c1 == 0) {
return false;
}
c2 = c1 - 1;
} while(!compareAndSetState(c1, c2));
return c2 == 0;
}
}
}